On the other hand, he said, California has committed to increasing its renewable-energy use to 50 percent by 2030. So, in the end, the decision made sense for that state.

But as for Arizona, Fenshaw said, the transition to clean energy would likely be just as long.

“Certainly, in Arizona, we have enough sunshine to take advantage of and transition to clean energy,” he said.

“We’ve been…encouraging (the Arizona Corporation Commission) to take all of the the benefits and values that rooftop solar provides to the electricity grid – and to society – into account when figuring out how to charge solar users.”

Last August, APS changed its “net metering” formula for solar users. The old one gave those users a full retail credit for each kilowatt-hour of surplus power they sent to the grid. The new APS solar credit is 12.9 cents per kilowatt hour. The utility said solar users were not contributing enough to maintain the electricity grid.

For SRP customers, any excess energy they produce is credited on their current bills, based on the energy’s retail price during the time it was generated. For example, if a customer generated excess energy during the morning, they would get a credit on their current bill at retail morning rates.

When asked why not allow new-home builders the choice of how to power their homes, Fanshaw said California is allowing some exceptions to the new requirement depending on the situation.

“For example…there are opportunities to do a shared or a community solar system,” he said.

As for added home-construction cost, “the commission…found that while adding solar would cost about $40 more per month on average, the the savings that customers would see because of solar…would be about $80 per month.”

The bottom line, Fanshaw said, is that California’s new rule will help many people.

“We believe it’s a huge win for the environment,” he said, “(It) will reduce pollution that contributes to global warming; improve air quality and public health.”

As for Arizona, “I don’t even know…if the Corporation Commission has the authority to to make this kind of decision in Arizona,” he said. “I think it is something that that a lot of stakeholders will have to look at.”